1. Field of the Invention
The present invention relates to a cushion assembly for a bicycle seat to improve its stability.
2. Description of Related Art
A typical conventional cushion assembly for a bicycle seat is shown in FIG. 6 of the drawings and generally includes a substantially tubular member 40 having a receptacle 41 defined therein and a peripheral hole 401 defined in an upper end of a periphery thereof, a coil spring 43 mounted in the receptacle 41 of the tubular member 40 with a lower end thereof resting on a bottom surface of the tubular member 40, a seat post 42 telescopically received in the receptacle 41 of the tubular member 40 and bearing against an upper end of the coil spring 43, and a threaded bolt 44 extending upwardly from the bottom of the tubular member 40 to engage with the seat post 42 at an upper end thereof. A seat (not shown) of a bicycle is securely mounted to the seat post 42.
The seat post 42 includes a vertical slit 420 defined in an upper end thereof such that a pin 421 is extended through the peripheral hole 401 in the tubular member 40 and the vertical slit 420 in the seat post 42 to prevent relative rotational movements between the seat post 42 and the tubular member 40. The seat post 42 further includes a transverse hole 422 defined in the upper end thereof and an end cap 45 having a second peripheral hole 47 therein is securely mounted to the upper end of the seat post 42 by inserting a pin 46 through the holes 47 and 422.
After assembly, a lower end of the seat post 42 defines a distance from the bottom surface of the tubular member 40. When the seat is loaded (e.g., a cyclist sits on the seat and cycles on a road), the seat post 42 is moved downwardly and thus compresses the spring 43, thereby providing a cushioning effect. However, such a cushion assembly still has several disadvantages. First, the hole 401 and the slit 420, provided to prevent relative rotational movements between the tubular member 40 and the seat post 42, are relatively small and thus require difficult alignment therebetween during assembly, thereby causing inconvenience in assembly, wasting labor, and increasing cost. In addition, provision of the slit 420 reduces a strength of the seat post 42 which may break when the bicycle seat is loaded with a relatively large weight. Second, a gap between the tubular member 40 and the seat post 42 is enlarged due to abrasion therebetween after a term of use, resulting in unstable engagement relationship between the tubular member 40 and the seat post 42. Third, relative rotational and shaking movements between the tubular member 40 and the seat post 42 (in other words, the bicycle seat) may result due to the enlargement of the gap.
Therefore, there has been a long and unfulfilled need for an improved cushion assembly for a bicycle seat post to mitigate and/or obviate the above problems.